The present invention relates to a power delivering apparatus, and more particularly to a gear for the power delivering apparatus of magnetic recording and reproducing system in which impact damage to the gear is prevented and noise caused by friction between the teeth of the gears is decreased.
In a conventional magnetic recording and reproducing system, when the recording mode or reproducing mode is selected, a magnetic tape in a cassette is pulled out by a tape taking device and placed on contact with a magnetic head. At the same time, a mechanical power delivering apparatus is operated to transmit the power to a hub within the cassette to drive the tape, the magnetic head records signal or reproduces the recorded signal according to the selected mode.
When the stop mode is selected or the recording or reproducing of the signal is otherwise finished, the tape is stopped and again taken into the cassette by the tape taking device.
FIGS. 1 and 2 are views showing a conventional power delivering apparatus for a recording and reproducing system. As shown in figures, a capstan motor 2 is mounted within main base 1 and a capstan gear 3 is axially mounted on the capstan motor 2. In the upper side of the main base 1, a conversion gear 5 in which a first timing gear is integrally formed is mounted so as to engage with the capstan gear 3. In the lower side of the main base 1, a center gear 7 is mounted. Second timing gear 6 is attached to the center gear 7. The first timing gear 4 and the second timing gear 6 are interconnected by a timing belt 8. On the upper end of the shaft of the center gear 7, a rotating lever 9 is mounted rotatably around the shaft. An idle gear 10 engaging the center gear 7 is mounted on the rotating lever 9 so as to be oscillated by the rotation of the center gear 7. On both sides of the idle gear 10, a winding reel 11 and a supplying reel 12 are mounted, so that the turning effect of the idle gear 10 is transmitted to the winding reel 11 and supplying reel 12 during the recording or reproducing mode, and the rewinding mode, respectively.
The conversion gear 5 comprises body unit 51, the first timing gear 4 being attached, and gear unit 52 at the outer periphery of the body unit 51. The gear unit 52 includes a plurality of teeth, so that the conversion gear 5 is engaged with the capstan gear 3.
In the above mentioned apparatus, when the reproducing or recording mode is selected, the magnetic tape is pulled out from the cassette by a tape taking device, not shown in figures, and placed in contact with the magnetic head. At the same time, the capstan motor 2 operates to rotate the capstan gear 3 mounted on the capstan motor 2 counter-clockwise, as shown in FIG. 1. Since the conversion gear 5 is engaged with the capstan gear 3, the conversion gear 5 rotates clockwise and the center gear 7 also rotates clockwise by the turning effect of the conversion gear 5 delivered through the timing belt 7 connecting the first timing gear 4 and the second timing gear 6.
By rotating the center gear 7, the rotating lever mounted at the upper end of the shaft of the center gear 7 rotates, so that the idle gear 10 oscillates in engagement with the winding reel 11. Since the idle gear 10 also engages the center gear 7, it rotates counter-clockwise. As a result, the winding reel 11 rotates clockwise. By this rotation of the winding reel 11, one of the cassette hubs is rotated for recording or reproducing.
In the rewinding mode, especially the fast rewinding mode, the capstan motor 2 is stopped and then driven in reverse to rewind the tape. In this mode, since the idle gear 10 oscillates to be engaged with the supplying reel 12 by the rotation of the rotating lever 9, the turning effect of the idle gear 10 by the reverse driving is delivered to the supplying reel 12 to rewind the tape quickly.
In general, the gears have a gap b between their teeth to permit easy engagement and prevent the effect dimension variations. This gap b causes noise by the friction between the engaging teeth in the fast rewinding mode. Thus, it is necessary to provide an impact absorption device for absorbing impact and decreasing friction between the teeth. In the conventional conversion gear for a power delivering apparatus, since there is no impact absorbing device noise is generated by friction between the engaging gear teeth and the gears are damaged by the impact on the gear teeth.